JP2009299098A - Metal production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal production method for separating a metal powder component from the mixture of metallic salt and metal powder, the method achieving reduction in energy necessary for the production. <P>SOLUTION: The mixture 1 of the metallic salt and the metal powder is supplied into a raw material charging zone 12 in a first hearth 10 divided with a skimmer 11 and heated to and held at the melting point or higher of the metallic salt and lower than the melting point of the metal powder by using a plasma 19a to form two layers comprising an upper layer (molten salt 2 resulting from melting of the metallic salt) and a lower layer (high concentrated solid-liquid mixture 3 having the increased concentration of the metal powder). Then, the molten salt 2 at the upper layer is exhausted from an exhausting port at the upper part of the first hearth and the high concentrated solid-liquid mixture 3 at the lower layer is exhausted from a lower layer exhausting port 14. Successively, the high concentrated solid-liquid mixture 3 is heated to and held at the melting point or higher of the metal powder, and the metal powder in the high concentrated solid-liquid mixture 3 is melted to form the molten metal, and an upper layer (molten salt 4) and a lower layer (molten metal 5) are formed, the molten metal 5 is separated from the molten salt 4, and the molten metal 5 is solidified to form an ingot 6. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a metal production method by separating a metal from a mixture of a molten metal salt and a metal, and relates to a metal production method having excellent energy efficiency.

As an industrial method for producing metal Ti, a crawl method in which TiCl ₄ is reduced with Mg is generally used. According to this method, a high-purity product can be produced. However, since the generated Ti powder settles in an aggregated state and is difficult to recover outside the reaction vessel, the operation must be performed in a batch mode. In addition, since TiCl ₄ is supplied in liquid form from above to the liquid surface of the molten Mg liquid in the reaction vessel, and the reaction is performed only near the liquid surface of the molten Mg liquid, avoiding a decrease in the utilization efficiency of TiCl ₄ , In order to avoid local exotherm accompanying the reaction, the feed rate of TiCl ₄ is limited. As a result, the manufacturing cost increases and the product price becomes very high.

Therefore, many researches and developments have been made on methods for producing metal Ti other than the crawl method. For example, in Patent Document 1, a molten metal salt of CaCl ₂ (hereinafter, also simply referred to as “molten salt”) is held in a reaction vessel, and metal Ca powder is supplied into the molten salt from above, to obtain a molten salt. A method is described in which Ca is dissolved therein, TiCl ₄ gas is supplied from below, and dissolved Ca and TiCl ₄ are reacted in a molten salt of CaCl ₂ . However, metallic Ca powder is extremely expensive, and in addition, highly reactive Ca is very difficult to handle, and this method cannot be established as an industrial metallic Ti production method.

Therefore, the inventors of the present invention need to reduce TiCl ₄ with Ca in order to industrially establish a method for producing metal Ti by Ca reduction, and economically use Ca in molten salt consumed in the reduction reaction. In addition to utilizing Ca produced by electrolysis of molten CaCl ₂ , a method of circulating and using this Ca, ie, the “OYIK method (Oic method)” was proposed (Patent Documents 2 and 3). reference).

Patent Document 2 describes a method in which Ca is generated and replenished by electrolysis, and molten CaCl ₂ with an increased Ca concentration is introduced into a reaction vessel and used to generate Ti particles by Ca reduction. Furthermore, a method of effectively suppressing back reaction accompanying electrolysis by using an alloy electrode (for example, Mg—Ca electrode) as a cathode is shown. Back reaction refers to the reaction between Ca in the molten salt and Cl ₂ generated by electrolysis when the molten salt from which Ti has been separated in the separation step is returned to the electrolytic cell, and back reaction occurs. , Current efficiency decreases.

  Patent Document 4 describes a method for producing Ti based on the OYIK method. As a method for separating Ti from a molten salt containing Ti particles produced by a reduction reaction, first, Ti is precipitated by centrifugal sedimentation in a high-temperature decanter. A method is described in which the grains are separated from the molten salt, and then the Ti grains are heated and melted by plasma irradiated from a plasma torch in a separation tank to remove the molten salt adhering to the Ti grains. The molten Ti is poured into a mold and becomes an ingot.

U.S. Pat. No. 4,820,339 JP 2005-133195 A JP 2005-133196 A International Publication No. 2007/105616 Pamphlet

  Since the high-temperature decanter described in Patent Document 4 is rotationally driven at a high temperature for separating Ti, it is difficult to continuously operate for a long time. Therefore, as a method that does not require rotational driving, the molten salt containing Ti particles is allowed to stand in the container, and when sedimentation is attempted, the Ti particles settle at the bottom of the container, and the Ti salt is contained in the molten salt. A high rate part was formed. The Ti grain content in the molten salt at this portion is estimated to be about 10% by weight.

  In this way, when trying to extract only the portion with a high Ti particle content formed in the molten salt from the container, the fluidity is poor, and the method of inhaling through the pipe inserted to the bottom of the container and the outlet at the bottom By any of the methods of providing and discharging, the piping or the discharge port was clogged, and it was not possible to extract sufficiently.

  The reason for this is that, in sedimentation separation, the molten salt is allowed to stand for a long time, so that the sedimented Ti particles are sintered into a porous mass. Then, when the sedimentation separation was performed, the Ti particle content in the molten salt that could actually be extracted and transferred to the separation tank was examined and found to be about 2% by weight.

  When the Ti grains in the molten salt are heated and melted in the separation tank, not only the Ti grains but also the molten salt having a low melting point is heated to the melting point of Ti. For this reason, if the Ti grain content in the molten salt is low, the amount of heating of the molten salt increases, and high power is required to generate plasma at a high output, resulting in poor energy efficiency.

  Then, this invention is a manufacturing method of the metal including the process of isolate | separating a metal from the solid-liquid mixture of a metal and molten salt, Comprising: It aims at providing the method excellent in energy efficiency.

  In order to solve the above-mentioned problems, the present inventors have studied a method for obtaining a solid-liquid mixture of a molten salt and a metal powder that can be transferred to a separation tank and has a high metal powder content.

  Then, using a hearth that is divided by a skimmer and has a region having an outlet at the bottom of the skimmer, in the region, the molten salt containing metal powder discharged from the high-temperature decanter is heated by plasma, and the melting point of the molten salt or higher When held at a temperature lower than the melting point of the metal, it can be separated into an upper layer consisting only of a molten salt and a lower layer consisting of a solid-liquid mixture of the molten salt and metal powder containing the metal powder at a high rate due to the difference in specific gravity. The solid-liquid mixture in the lower layer could be discharged from the outlet at the bottom of the skimmer with a high metal powder content.

  In this manner, the reason why the solid-liquid mixture can be discharged while the metal powder content is high is that in this hearth, there is no pressure loss on both the molten salt input side and the discharge port at the bottom of the skimmer, and the metal powder is sintered. Therefore, it is considered that not only the upper layer but also the lower layer could easily flow. Therefore, it was possible to easily extract a solid-liquid mixture containing the lower layer metal powder at a high rate by discharging only the upper layer molten salt from the hearth.

  The solid-liquid mixture containing the metal powder obtained by using such a hearth at a high rate can be transferred to the separation tank as it is. Therefore, it is possible to improve the energy efficiency when melting and separating the molten salt and metal of the solid-liquid mixture.

  The present invention has been made on the basis of such findings, and the gist thereof resides in the following metal production method.

The manufacturing method of a metal provided with the process of following (a)-(f).
(A) The raw material charging region of the first hearth provided with a raw material charging region that is divided by a skimmer and has an upper layer outlet at the upper part and a lower layer outlet at the lower part of the skimmer has a melting point higher than that of the metal salt and the metal salt. Supplying a mixture with metal powder made of high metal,
(B) The mixture in the raw material charging region of the first hearth is heated and held at a temperature equal to or higher than the melting point of the metal salt and lower than the melting point of the metal using plasma, and by the difference in specific gravity between the metal salt and the metal, The upper layer made of a molten salt in which the metal salt is melted and the lower layer made of a high-concentration solid-liquid mixture in which the molten salt and the metal powder are mixed and the concentration of the metal powder is higher than the mixture are formed. Process,
(C) discharging the upper layer molten metal salt from the upper layer outlet and discharging the lower layer high-concentration solid-liquid mixture from the lower layer outlet;
(D) heating the high-concentration solid-liquid mixture discharged from the lower layer outlet to a melting point of the metal or higher to melt the metal powder in the high-concentration solid-liquid mixture to obtain a liquid mixture;
(E) maintaining the liquid mixture at or above the melting point of the metal, and forming an upper layer made of the molten salt and a lower layer made of a molten metal in which the metal powder is melted by a specific gravity difference; and (f) from the molten salt Solidifying the separated molten metal.

  The metal salt in the above (a) may be in a solid state or a liquid state. Further, the “metal powder concentration” means the content of the metal powder in the raw material or solid-liquid mixture, and is also simply referred to as “metal concentration”.

In the metal production method, CaCl ₂ can be used as the metal salt and Ti can be used as the metal. The metal may be a Ti alloy as well as a Ti simple substance.

  In the metal manufacturing method, the first hearth is divided into the raw material input region and the high metal concentration region by the skimmer, and the raw material input region and the high metal concentration region are formed of the skimmer. The high-concentration solid-liquid mixture may be discharged to the high-concentration metal region by communicating with the lower-layer discharge port provided below.

  In the step (c) of the metal production method, the lower-layer high-concentration solid-liquid mixture is discharged to a second hearth, and the step (d) and the step (e) are performed in the second hearth. The high-concentration solid-liquid mixture may be heated using plasma, or the lower-layer high-concentration solid-liquid mixture may be discharged into the metal high-concentration region, and the steps (d) and (e ) May be performed in the metal high concentration region by heating the high concentration solid-liquid mixture using plasma. In the step (c), the high-concentration solid-liquid mixture may be discharged by swinging the first hearth.

  According to the metal production method of the present invention, since a solid-liquid mixture having a high concentration of metal powder can be supplied to the separation tank, the amount of molten salt when the metal powder is melted together with the molten salt in the separation tank is reduced. Energy efficiency can be improved.

  The manufacturing method of the metal of this invention is a manufacturing method of a metal provided with the above-mentioned process (a)-(f).

<First Embodiment>
FIG. 1 is a diagram showing a configuration example of an apparatus used for a metal manufacturing method according to the first embodiment of the present invention. As shown in FIG. 1, in this apparatus, a first hearth 10, a second hearth (separation tank) 20, and a mold 30 are arranged in this order from the top. The external appearance of the apparatus is constituted by a chamber (not shown), and the inside of the chamber is maintained in an inert gas atmosphere such as argon.

  The first hearth 10 is divided into a raw material charging region 12 and a metal high concentration region (Ti high concentration region) 13 by a skimmer 11. The upper edge of the side wall 16 on the raw material input region side is set higher than the upper edge of the side wall 17 on the Ti high concentration region side, and the upper edge of both the side walls 16 and 17 discharges fluid such as liquid. A groove (not shown) is formed.

A raw material 1 made of a mixture of CaCl ₂ that is a metal salt and Ti powder that is a metal powder is input to the raw material input region 12. The raw material charging region 12 and the Ti high concentration region 13 are communicated with each other through a lower layer outlet 14 provided at the lower part of the skimmer 11. Above the first hearth 10, a plasma torch 19 capable of swinging and capable of irradiating the raw material charging area 12 and the Ti high concentration area 13 with the plasma 19a is disposed.

  Similarly, the second hearth 20 is divided into a molten salt inflow region 22 and a molten Ti region 23 by a skimmer 21, and both the regions 22 and 23 are formed by a communication port 24 provided at the lower part of the skimmer 21. Communicate. The upper edge of the side wall 26 on the molten salt inflow region side is set to be higher than the upper edge of the side wall 27 on the molten Ti region side. A groove (not shown) is formed.

  The molten salt inflow region 22 is disposed at a position where it can receive the liquid or solid-liquid mixture discharged from the Ti high concentration region 13 of the first hearth 10. Further, a plasma torch 29 capable of swinging motion and capable of irradiating the molten salt inflow region 22 and the molten Ti region 23 with the plasma 29a is disposed above the second hearth 20.

As the first hearth 10 and the second hearth 20, for example, a copper water-cooled hearth can be used, and as the skimmers 11 and 21, ceramics such as Y ₂ O ₃ (yttria) and Al ₂ O ₃ (alumina), for example. A board made of steel can be used.

Next, the operation in the first hearth 10 will be described. Raw material 1 is charged from the raw material charging region 12, and plasma 19a is irradiated from the plasma torch 19 and heated to a melting point of CaCl ₂ or higher and lower than that of Ti to produce a solid-liquid mixture of Ti powder and molten salt of CaCl _2. Let

This solid-liquid mixture is maintained at a melting point of CaCl ₂ (780 ° C.) or higher and lower than the melting point of Ti (1680 ° C.), and Ti powder is precipitated by the specific gravity difference between Ti and CaCl _2, and the upper layer (molten salt 2) And upper and lower two layers of the lower layer (high concentration solid-liquid mixture 3 with an increased Ti powder content). In this case, the holding temperature can be 800 ° C. or higher and 1000 ° C. or lower.

Further, as a metal salt, a mixture of CaCl ₂ and KCl or the like may be used. In this case, since the melting point of the metal salt is lower than that of CaCl ₂ , the holding temperature is 750 ° C. or more and 1000 ° C. or less. do it.

  When the raw material 1 is additionally charged into the raw material charging region 12 as the melting of the raw material 1 proceeds, the added raw material 1 is also melted. And the liquid level rises in the raw material charging region 12 and the Ti high concentration region 13 in a state where the solid-liquid mixture is separated into upper and lower layers.

  Further, when the raw material 1 is added and the liquid level becomes higher than the upper edge of the side wall 17 on the Ti high concentration region side, the molten salt in the upper layer on the Ti high concentration region 13 side is changed from the first hearth 10 to the second hearth. It starts to be discharged to 20. When all of the molten salt in the upper layer is discharged, the Ti high concentration region 13 is occupied by only the high concentration solid / liquid mixture 3, and the high concentration solid / liquid mixture 3 is discharged to the second hearth 20.

  When the Ti concentration in the raw material 1 is 2 to 10%, the Ti concentration in the high-concentration solid-liquid mixture 3 discharged from the first hearth 10 increases to 30 to 60%. Hereinafter, the Ti content (wt%) in the raw material or solid-liquid mixture is referred to as Ti concentration.

On the other hand, when the liquid level rises also in the raw material charging region 12 and the liquid level becomes higher than the upper edge of the side wall 16 on the raw material charging region side, the molten salt 2 starts to be discharged. The discharged molten salt 2 can be reused for the reduction reaction of TiCl ₄ .

  The addition of the raw material 1 may be performed continuously little by little, or may be performed after a predetermined time. When the time interval is long, the molten salt 2 and the high concentration solid / liquid mixture 3 are intermittently discharged from the first hearth 10.

Next, the operation in the second hearth 20 that is a separation tank for separating the molten salt and the metal will be described. A plasma 29a is irradiated from the plasma torch 29 to the high-concentration solid-liquid mixture 3 (including a small amount of molten salt that first flows) flowing into the molten salt inflow region 22 of the first hearth 10 from the first hearth 10; It heats more than the melting | fusing point of Ti, and makes the whole high concentration solid-liquid mixture 3 a molten state. Then, holding the melt above the melting point of Ti, precipitated molten Ti 5 by the specific gravity difference between Ti and CaCl _2, an upper layer (molten salt 4), it is separated into upper and lower layers of the lower layer (molten Ti 5).

  When the inflow of the high-concentration solid-liquid mixture 3 from the first hearth 10 proceeds, the liquid level rises in the molten salt inflow region 22 and the molten Ti region 23 in a state where the melt is separated into two layers, and the molten Ti Molten salt begins to be discharged from the upper edge of the side wall 27 on the region side to the mold 30. When all the molten salt is discharged, the molten Ti region 23 is occupied by only the molten Ti5, the molten Ti5 is discharged into the mold 30, and the Ti ingot 6 is cast.

On the other hand, when the liquid level also rises in the molten salt inflow region 22 and the liquid level becomes higher than the upper edge of the side wall 26 on the molten salt inflow region side, the molten salt 4 starts to be discharged. This molten salt 4 can also be reused for the reduction reaction of TiCl ₄ .

  FIG. 1 shows a steady state after the discharge of the molten salt from the Ti high concentration region 13 of the first hearth 10 and the molten Ti region 23 of the second hearth 20 is completed. In the steady state, in the first hearth 10, the high-concentration solid-liquid mixture 3 is discharged from the Ti high-concentration region 13, and the molten salt 2 is discharged from the raw material charging region 12, and in the second hearth 20, the melt is melted from the molten Ti region 23. The molten salt 4 is discharged from the Ti5 and molten salt inflow region 22.

As described above, according to the manufacturing method of the present invention, when separating Ti and CaCl ₂ contained in the raw material, first, at the first hearth 10, at a relatively low temperature that is higher than the melting point of CaCl ₂ and lower than the melting point of Ti. A high-concentration solid-liquid mixture with an increased Ti concentration can be generated and transferred to the second hearth 20 which is a separation tank with a high Ti concentration. Subsequently, in the second hearth 20, the entire high-concentration solid-liquid mixture 3 in which CaCl ₂ is reduced is melted at a high temperature equal to or higher than the melting point of Ti, and the molten Ti 5 and the molten salt 4 are separated.

Therefore, the amount of CaCl ₂ to be heated to the melting point of Ti or more can be reduced as compared with the conventional method in which the whole raw material containing Ti is melted at a high temperature by one hearth to separate Ti. For this reason, the energy required to separate Ti and CaCl ₂ contained in the raw material can be greatly reduced, the amount of evaporation of CaCl ₂ inside the chamber surrounding the apparatus can be reduced, and contamination inside the chamber can be reduced. In addition, damage to the exhaust system can be reduced.

In the steady state shown in FIG. 1, since Ti has a higher specific gravity than CaCl ₂ , the liquid level on the raw material input region 12 side in the first hearth 10 is higher than that on the Ti high concentration region 13 side. In the second hearth 20, the liquid level on the molten salt inflow region 22 side is stabilized in a state higher than the molten Ti region 23 side.

  Therefore, the upper edge of the side wall 16 on the raw material input region side is set higher than the upper edge of the side wall 17 on the Ti high concentration region side, and the upper edge of the side wall 26 on the molten salt inflow region side is set on the side wall 27 on the molten Ti region side. Can be set higher than the upper edge. Thereby, the depth of the upper layer (molten salt 2, 4) in the raw material charging region 12 and the molten salt inflow region 22 can be secured, and the distance from the discharge port to the boundary between the upper layer and the lower layer can be increased. Since more powder or molten Ti can be settled, the Ti content in the discharged molten salts 2 and 4 can be reduced.

<Second Embodiment>
FIG. 2 is a diagram showing a configuration example of an apparatus used in the metal manufacturing method according to the second embodiment of the present invention. The second embodiment is the same as the first embodiment except that the high-concentration solid-liquid mixture is melted in the first hearth. In the figure, substantially the same parts are denoted by the same reference numerals. ing.

In the steady state of the present embodiment, in the raw material charging region 12 of the first hearth 10, as in the first embodiment, the molten solid-liquid mixture of the raw material 1 is maintained at a melting point of CaCl ₂ or higher and lower than a melting point of Ti. The upper layer (molten salt 2) and the lower layer (high concentration solid-liquid mixture 3) are separated into two upper and lower layers. The lower-layer high-concentration solid-liquid mixture 3 flows into the Ti high-concentration region 13 from the lower-layer outlet 14 provided in the lower part of the skimmer 11.

  In the Ti high concentration region 13, the vicinity of the liquid surface is held above the melting point of Ti by the irradiation of the plasma 19 a on the liquid surface of the high concentration solid / liquid mixture 3, and the Ti powder in the high concentration solid / liquid mixture 3 is melted. Therefore, in the vicinity of the skimmer 11 in the Ti high concentration region 13, the high concentration solid-liquid mixture 3 flowing from the raw material input region 12 is exposed, and in the vicinity of the side wall 17 on the Ti high concentration region side, an upper layer made of the molten salt 4; The exposed high-concentration solid-liquid mixture 3 is separated into two upper and lower layers where the molten Ti5 in which the Ti powder is melted is settled.

  The above-described temperature adjustment of the liquid level using the plasma torch 19 is realized by adjusting the swing speed of the plasma torch 19 and adjusting the residence time of the plasma torch 19 near the liquid level in each region. Is possible.

  When the liquid level in the Ti high concentration region 13 rises due to the addition of the raw material 1 to the raw material input region 12, the molten salt 4 and the molten Ti5 are supplied from the upper edge of the side wall 17 on the Ti high concentration region side to the second hearth 20. To be discharged.

In the second hearth 20, when the molten salt 4 and molten Ti5 flowing into the molten salt inflow region 22 from the first hearth 10 are continuously heated and maintained above the melting point of Ti by the plasma 29a, the specific gravity of Ti and CaCl ₂ is increased. Due to the difference, the molten Ti5 settles and separates into an upper layer (molten salt 4) and a lower layer (molten Ti5). Then, similarly to the first embodiment, the molten salt 4 is discharged from the molten salt inflow region 22 of the second hearth 20, the molten Ti5 is discharged to the mold 30, and the Ti ingot 6 is cast.

  As described above, in the Ti high concentration region 13 of the first hearth 10, the liquid surface of the high concentration solid-liquid mixture 3 is maintained at the melting point of Ti or higher so that the fluidity of the high concentration solid-liquid mixture 3 is poor. Even when it is difficult to be discharged to the second hearth 20, the molten salt 4 and molten Ti5 can be melted and discharged.

<Third Embodiment>
FIG. 3 is a diagram showing a configuration example and operation of an apparatus used for a metal manufacturing method according to the third embodiment of the present invention. The third embodiment is the same as the first embodiment except that the first hearth can be swung, and FIG. 3 shows only the first hearth and is substantially the first. The same parts as those in the embodiment are denoted by the same reference numerals.

  In the present embodiment, the first hearth 10 is lowered by the support shaft 18 provided on the lower surface when the raw material input region 12 side is raised, the Ti high concentration region 13 side is lowered, and when the raw material input region 12 side is lowered, the Ti high concentration region 13 side is It is swingably supported so as to rise.

  FIG. 3 (a) shows a state in which the discharge of the molten salt 2 and the high-concentration solid-liquid mixture 3 is stopped in a steady state, and FIG. 3 (b) lowers the raw material charging region 12 side of the first hearth 10; In the state where the molten salt 2 is being discharged, the same figure (c) further lowers the raw material charging region 12 side, and the state in which the discharge of the molten salt 2 from the first hearth 10 has been completed, FIG. It is a figure which shows the state which descend | falls the Ti high concentration area | region 13 side of the 1st hearth 10, and is discharging the high concentration solid-liquid mixture 3. FIG.

  From the horizontal state shown in FIG. 3A, as shown in FIG. 3B, the raw material charging area 12 of the first hearth 10 is lowered and the molten salt 2 is discharged. At this time, care should be taken not to wind up the high-concentration solid-liquid mixture 3 and to prevent the molten salt 2 from moving from the lower end of the skimmer 11 to the Ti high-concentration region 13.

  Then, as shown in FIG. 3 (c), when the raw material charging region 12 side is further lowered and the discharge of the predetermined amount of the molten salt 2 is completed, the Ti high concentration region 13 side is moved as shown in FIG. 3 (d). Then, the high concentration solid / liquid mixture 3 is discharged.

  When the first hearth 10 is returned to the horizontal position during the transition from the state shown in FIG. 3C to the state shown in FIG. 3D, the liquid level does not separate from the lower end of the skimmer 11. It is desirable to leave the concentrated solid-liquid mixture 3. This is because when the liquid surface is separated from the lower end of the skimmer 11, the molten salt 2 on the raw material input region 12 side moves to the Ti high concentration region 13 side, and the Ti concentration in the high concentration solid-liquid mixture 3 is reduced and newly added. This is because the molten salt 2 generated when the raw material added to the melted material moves to the Ti high concentration region 13 side.

After the discharge of the high-concentration solid-liquid mixture 3 is completed, the first hearth 10 is returned to the horizontal state again as shown in FIG. During this series of swinging operations, the temperature of the molten salt 2 and the high-concentration solid-liquid mixture 3 is maintained at a melting point of CaCl ₂ or higher and lower than that of Ti.

  By swinging the first hearth 10 in this manner, the second hearth 20 can be forcibly discharged even when the fluidity of the high-concentration solid-liquid mixture 3 is poor.

  In the case of swinging, the lowering of the raw material charging region 12 shown in FIGS. 3B and 3C is omitted, and the Ti high concentration region as shown in FIG. 3D directly from the state of FIG. The 13 side may be lowered. However, in order to prevent the molten salt 2 on the raw material charging region 12 side from moving to the Ti high concentration region 13 side, prior to discharging the high concentration solid-liquid mixture 3, It is desirable to discharge.

  Such swinging may be performed not only by the first hearth 10 but also by the second hearth 20. Thereby, even when the fluidity of the molten Ti5 is poor, it can be discharged from the second hearth 20 to the mold 30.

  In order to confirm the effect of the metal production method of the present invention, the following production experiment was conducted and the result was evaluated.

1. Production Conditions Using the production apparatus shown in FIG. 1, the raw material was separated into molten salt and Ti, and a Ti ingot was cast. Table 1 shows the conditions of the manufacturing apparatus used. The atmosphere in the chamber was an argon atmosphere, and the same first hearth and second hearth were used.

Table 2 shows the conditions of the raw material composition, the weight, and the melting current amount and the melting time in the first hearth and the second hearth. The raw material used was 3000 g of a mixture containing ₂ % by weight of Ti powder and 98% by weight of CaCl ₂ .

The melting current is a current that flows through the plasma torch. In the comparative example, the melting current in the first hearth is set so that the entire raw material is melted. In the present invention example, only CaCl _{2 of} the raw material is melted to form a solid-liquid mixture of Ti powder and molten salt. Set to do. The melting current in the second hearth was set so that the entire raw material was melted in both the comparative example and the inventive example.

2. Test Results Regarding Ti ingot casting performed under the above conditions, as shown in Table 3, the evaporation amount of CaCl _{2 in} the first hearth, Ti concentration in the high-concentration solid-liquid mixture, availability of casting of Ti ingot, and use The total energy was evaluated as an index. The total amount of energy used is used in the first torch plasma torch and the second torch plasma torch between the start of charging the raw material and the ingot casting. The total amount of energy spent. The amount of evaporation of CaCl ₂ and the total amount of energy used in the first hearth are shown as relative amounts in comparison example 1.

As shown in Table 3, it was possible to cast a Ti ingot in both the comparative example and the inventive example. Furthermore, in the present invention example, the amount of melting current in the first hearth was set to be smaller than that in the comparative example, so that the amount of evaporation of CaCl _{2 and} the amount of energy used in the first hearth were made lower than those in the comparative example. I was able to.

  In the metal production method of the present invention, in the first hearth, in the solid-liquid mixture produced by holding the raw material at a temperature at which only the metal salt melts and the metal powder does not melt, the molten salt is removed to remove the metal powder concentration. Since the entire solid-liquid mixture is melted in the second hearth after the temperature of the metal is raised, the molten salt heated to the melting point of the metal powder or more can be reduced, so that the energy efficiency in separating the metal from the raw material can be reduced. Can be improved.

  Therefore, according to the method for producing a metal of the present invention, metal chloride is obtained in a state of being mixed with a molten salt, and is effectively used, for example, in the production of metal Ti by reducing metal chlorides in the molten salt. can do.

It is a figure which shows the structural example of the apparatus used for the manufacturing method of the metal which concerns on the 1st Embodiment of this invention. It is a figure which shows the structural example of the apparatus used for the manufacturing method of the metal which concerns on the 2nd Embodiment of this invention. It is a figure which shows the structural example and operation | movement of an apparatus used for the manufacturing method of the metal which concerns on the 3rd Embodiment of this invention, (a) stopped discharge | emission of molten salt and a high concentration solid-liquid mixture in the steady state. State (b) is a state in which the raw material input region side of the first hearth is lowered and the molten salt is discharged. (C) is a state in which the raw material input region 12 side is further lowered and melted from the first hearth. (D) is a diagram showing a state in which the high concentration solid-liquid mixture is discharged by lowering the Ti high concentration region side of the first hearth.

Explanation of symbols

1 Raw Material 2 Molten Salt 3 High Concentration Solid-Liquid Mixture 4 Molten Salt 5 Molten Ti
6 Ti Ingot 10 1st Hearth 11 Skimmer 12 Raw Material Input Area 13 Metal High Concentration Area (Ti High Concentration Area)
14 Lower layer outlet 16 Side wall (raw material input area side)
17 Side wall (Ti high concentration region side)
18 Support shaft 19 Plasma torch 20 Second hearth (separation tank)
21 Skimmer 22 Molten salt inflow region 23 Molten Ti region 24 Communication port 26 Side wall (molten salt inflow region side)
27 Side wall (molten Ti region side)
29 Plasma Torch 30 Mold

Claims (6)

The manufacturing method of a metal provided with the process of following (a)-(f).
(A) The raw material charging region of the first hearth provided with a raw material charging region that is divided by a skimmer and has an upper layer outlet at the upper part and a lower layer outlet at the lower part of the skimmer has a melting point higher than that of the metal salt and the metal salt. Supplying a mixture with metal powder made of high metal,
(B) The mixture in the raw material charging region of the first hearth is heated and held at a temperature equal to or higher than the melting point of the metal salt and lower than the melting point of the metal using plasma, and by the difference in specific gravity between the metal salt and the metal, The upper layer made of a molten salt in which the metal salt is melted and the lower layer made of a high-concentration solid-liquid mixture in which the molten salt and the metal powder are mixed and the concentration of the metal powder is higher than the mixture are formed. Process,
(C) discharging the upper layer molten metal salt from the upper layer outlet and discharging the lower layer high-concentration solid-liquid mixture from the lower layer outlet;
(D) heating the high-concentration solid-liquid mixture discharged from the lower layer outlet to a melting point of the metal or higher to melt the metal powder in the high-concentration solid-liquid mixture to obtain a liquid mixture;
(E) maintaining the liquid mixture at or above the melting point of the metal, and forming an upper layer made of the molten salt and a lower layer made of a molten metal in which the metal powder is melted by a specific gravity difference; and (f) from the molten salt Solidifying the separated molten metal. The method for producing a metal according to claim 1, wherein the metal salt is CaCl ₂ and the metal is Ti.   The first hearth is divided into the raw material input region and the metal high concentration region by the skimmer, and the raw material input region and the metal high concentration region are provided below the skimmer. The method for producing a metal according to claim 1 or 2, wherein the high-concentration solid-liquid mixture is discharged through the outlet and discharged into the high-concentration metal region. In the step (c), discharging the lower layer high-concentration solid-liquid mixture to a second hearth,
3. The metal according to claim 1, wherein the step (d) and the step (e) are performed by heating the high-concentration solid-liquid mixture using plasma in the second hearth. 4. Manufacturing method. In the step (c), the lower-layer high-concentration solid-liquid mixture is discharged to the metal high-concentration region,
The method for producing a metal according to claim 3, wherein the step (d) and the step (e) are performed by heating the high-concentration solid-liquid mixture using plasma in the metal high-concentration region. .   6. The method for producing a metal according to claim 1, wherein in the step (c), the high-concentration solid-liquid mixture is discharged by swinging the first hearth.

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